This invention relates to helmet liners and a method of making such liners which in their formation are fitted to the head of the user. In specialised helmets such as are employed, for example, by aircrew personnel the proper protection and comfort of the user dictates that the helmet is an accurate fit and that the closeness of the fit be accomplished by use of a shock absorbing liner which is tailored to the shape of the head of the user and to the interior of the helmet shell. References herein to the interior of the helmet shell are to be understood as referring to the inner surface of the shell or of a fixed impact absorbing lining material provided in the shell.